Superconductivity is the phenomenon wherein certain metals, alloys and compounds, such as YBCO, REBCO and BSCCO, at very low temperatures lose electrical resistance so that they have infinite electrical conductivity. It is important in the use of superconducting devices that the cooling, i.e. refrigeration, provided to the superconducting device not fall below a certain level lest the wire lose its ability to superconduct and the function of the device be compromised. Often this refrigeration is supplied by a cryogenic liquid and consumed in the device by warming of the liquid. Most devices will not tolerate a gas phase of the coolant due to electrical considerations.